some minor optimizations to ray/aabb intersection, does make a difference though...

Author: rms80

intersection/IntrRay3AxisAlignedBox3.cs

@@ -87,60 +87,86 @@ public static bool Intersects(ref Ray3d ray, ref AxisAlignedBox3d box, double ex
             Vector3d AWdU = Vector3d.Zero;
             Vector3d DdU = Vector3d.Zero;
             Vector3d ADdU = Vector3d.Zero;
-            Vector3d AWxDdU = Vector3d.Zero;
             double RHS;
 
             Vector3d diff = ray.Origin - box.Center;
             Vector3d extent = box.Extents + expandExtents;
 
-            WdU[0] = ray.Direction.x; // ray.Direction.Dot(Vector3d.AxisX);
-            AWdU[0] = Math.Abs(WdU[0]);
-            DdU[0] = diff.x; // diff.Dot(Vector3d.AxisX);
-            ADdU[0] = Math.Abs(DdU[0]);
-            if (ADdU[0] > extent.x && DdU[0] * WdU[0] >= (double)0) {
+            WdU.x = ray.Direction.x; // ray.Direction.Dot(Vector3d.AxisX);
+            AWdU.x = Math.Abs(WdU.x);
+            DdU.x = diff.x; // diff.Dot(Vector3d.AxisX);
+            ADdU.x = Math.Abs(DdU.x);
+            if (ADdU.x > extent.x && DdU.x * WdU.x >= (double)0) {
                 return false;
             }
 
-            WdU[1] = ray.Direction.y; // ray.Direction.Dot(Vector3d.AxisY);
-            AWdU[1] = Math.Abs(WdU[1]);
-            DdU[1] = diff.y; // diff.Dot(Vector3d.AxisY);
-            ADdU[1] = Math.Abs(DdU[1]);
-            if (ADdU[1] > extent.y && DdU[1] * WdU[1] >= (double)0) {
+            WdU.y = ray.Direction.y; // ray.Direction.Dot(Vector3d.AxisY);
+            AWdU.y = Math.Abs(WdU.y);
+            DdU.y = diff.y; // diff.Dot(Vector3d.AxisY);
+            ADdU.y = Math.Abs(DdU.y);
+            if (ADdU.y > extent.y && DdU.y * WdU.y >= (double)0) {
                 return false;
             }
 
-            WdU[2] = ray.Direction.z; // ray.Direction.Dot(Vector3d.AxisZ);
-            AWdU[2] = Math.Abs(WdU[2]);
-            DdU[2] = diff.z; // diff.Dot(Vector3d.AxisZ);
-            ADdU[2] = Math.Abs(DdU[2]);
-            if (ADdU[2] > extent.z && DdU[2] * WdU[2] >= (double)0) {
+            WdU.z = ray.Direction.z; // ray.Direction.Dot(Vector3d.AxisZ);
+            AWdU.z = Math.Abs(WdU.z);
+            DdU.z = diff.z; // diff.Dot(Vector3d.AxisZ);
+            ADdU.z = Math.Abs(DdU.z);
+            if (ADdU.z > extent.z && DdU.z * WdU.z >= (double)0) {
                 return false;
             }
 
             Vector3d WxD = ray.Direction.Cross(diff);
+            Vector3d AWxDdU = Vector3d.Zero;
 
-            AWxDdU[0] = Math.Abs(WxD.x); // Math.Abs(WxD.Dot(Vector3d.AxisX));
-            RHS = extent.y * AWdU[2] + extent.z * AWdU[1];
-            if (AWxDdU[0] > RHS) {
+            AWxDdU.x = Math.Abs(WxD.x); // Math.Abs(WxD.Dot(Vector3d.AxisX));
+            RHS = extent.y * AWdU.z + extent.z * AWdU.y;
+            if (AWxDdU.x > RHS) {
                 return false;
             }
 
-            AWxDdU[1] = Math.Abs(WxD.y); // Math.Abs(WxD.Dot(Vector3d.AxisY));
-            RHS = extent.x * AWdU[2] + extent.z * AWdU[0];
-            if (AWxDdU[1] > RHS) {
+            AWxDdU.y = Math.Abs(WxD.y); // Math.Abs(WxD.Dot(Vector3d.AxisY));
+            RHS = extent.x * AWdU.z + extent.z * AWdU.x;
+            if (AWxDdU.y > RHS) {
                 return false;
             }
 
-            AWxDdU[2] = Math.Abs(WxD.z); // Math.Abs(WxD.Dot(Vector3d.AxisZ));
-            RHS = extent.x * AWdU[1] + extent.y * AWdU[0];
-            if (AWxDdU[2] > RHS) {
+            AWxDdU.z = Math.Abs(WxD.z); // Math.Abs(WxD.Dot(Vector3d.AxisZ));
+            RHS = extent.x * AWdU.y + extent.y * AWdU.x;
+            if (AWxDdU.z > RHS) {
                 return false;
             }
 
             return true;
         }
 
 
+        /// <summary>
+        /// Find intersection of ray with AABB, without having to construct any new classes.
+        /// Returns ray T-value of first intersection (or double.MaxVlaue on miss)
+        /// </summary>
+        public static bool FindRayIntersectT(ref Ray3d ray, ref AxisAlignedBox3d box, out double RayParam)
+        {
+            double RayParam0 = 0.0;
+            double RayParam1 = double.MaxValue;
+            int Quantity = 0;
+            Vector3d Point0 = Vector3d.Zero;
+            Vector3d Point1 = Vector3d.Zero;
+            IntersectionType Type = IntersectionType.Empty;
+            IntrLine3AxisAlignedBox3.DoClipping(ref RayParam0, ref RayParam1, ref ray.Origin, ref ray.Direction, ref box,
+                      true, ref Quantity, ref Point0, ref Point1, ref Type);
+
+            if (Type != IntersectionType.Empty) {
+                RayParam = RayParam0;
+                return true;
+            } else {
+                RayParam = double.MaxValue;
+                return false;
+            }
+        }
+
+
+
 
     }
 }

spatial/DMeshAABBTree.cs

@@ -25,6 +25,7 @@ namespace g3
     ///   - FindNearestTriangles(otherAABBTree, maxdist)
     ///   - IsInside(point)
     ///   - WindingNumber(point)
+    ///   - FastWindingNumber(point)
     ///   - DoTraversal(generic_traversal_object)
     /// 
     /// </summary>
@@ -2238,11 +2239,10 @@ double box_ray_intersect_t(int iBox, Ray3d ray)
             Vector3f e = box_extents[iBox];
             AxisAlignedBox3d box = new AxisAlignedBox3d(ref c, e.x + box_eps, e.y + box_eps, e.z + box_eps);
 
-            IntrRay3AxisAlignedBox3 intr = new IntrRay3AxisAlignedBox3(ray, box);
-            if (intr.Find()) {
-                return intr.RayParam0;
+            double ray_t = double.MaxValue;
+            if (IntrRay3AxisAlignedBox3.FindRayIntersectT(ref ray, ref box, out ray_t)) {
+                return ray_t;
             } else {
-                Debug.Assert(intr.Result != IntersectionResult.InvalidQuery);
                 return double.MaxValue;
             }
         }